Waterbeds have been accepted by the general public as being both serviceable and desirable. Further, they have been continuously improved since their introduction and generally employ a surrounding frame which supports the peripheral vertical edges of a rectangular envelope (mattress) which is filled with water. Such devices have been patented and typical patents on waterbeds include the air frame constructions, such as shown in U.S. Pat. No. 3,778,852 issued to Penn et al, or multiple compartment matresses such as shown in U.S. Pat. No. 3,766,579 issued to Shields. Further, highly desirable innovations may be incorporated in such water mattresses as illustrated in U.S. Pat. No. 3,864,768 issued to Fraige et al, which increases both comfort and conveniences of such water mattresses.
Since water mattresses contain a large amount of water creating substantial hydrostatic pressures within the mattress, which are increased when the mattress is in use, mattress construction is critical since they are normally manufactured of thin thermal plastic films, such as polyvinyl chloride, forming a box-like envelope that must contain the water without leakage. Thus, a number of techniques have been developed for the construction of water mattresses such as those illustrated in U.S. Pat. No. 3,753,823 issued to Kuss and U.S. Pat. No. 3,753,819 issued to Mollura. In addition, general construction techniques relating to thermal plastic film, such as polyvinyl chloride, are illustrated in U.S. Pat. No. 2,440,664 issued to Irons; U.S. Pat. No. 3,362,302 issued to Friedman; and U.S. Pat. No. 3,619,863 issued to Ciabani.
Even with all these known construction techniques a considerable number of problems still exist in obtaining a leak-proof box-like enclosure (water mattress) for waterbeds. Of course when an air frame construction is employed an additional separate leak-proof pneumatic enclosure must be fabricated about the basic enclosure causing additional problems in obtaining a quality waterbed.
The areas of persistent leakage in water mattresses are usually located in the seams and corners of the box-like envelope forming the water mattress. Obviously, because of the relatively high hydrostatic pressures when the mattress is in use, there is considerable strain on all the seams and, as a result, both structural failures and improper welding techniques can often cause water leakage problems, that first appear when the mattress is first put into service.
The current invention is related to a mattress which is manufactured by techniques wherein the water mattress includes improved seams and corner constructions that give the mattress increased service life and decrease the problems of leakage resulting from structural failure in such areas or from improper bonding.
Another collateral object of the instant invention is a technique for improving the installation of the filler valve through which water can be pumped to fill the water mattress and through which air is expelled from the interior of the mattress when the mattress is filled with water.
Other objects will be apparent from the description of the water mattress and the method of construction more specifically set out in detail herein.